84522.20131010 Occultation October 10, 2013

(last updated 2013 08 21)

Observer Notes / Finder Charts

 

Across the globe pictured above, the three solid lines correspond to the northern limit, centerline, and southern limit of 84522s shadow. The northern and southern limits correspond to a radius of 615 km. The upper and lower dashed lines indicate 3-sigma errors. The shaded area represents where the sun is more than 12 degrees below the horizon.
Table 1: Prediction Details
84522 Geocentric Mid-time (yyyy month dd hh:mm:ss)

2013 October 10 06:41:53± 00:01:591 UT

84522 Minimum Geocentric Separation 0.001± 0.1111 arcsec
Position Angle (84522 relative to the star; measured north through east) 171.35 degrees
Geocentric Velocity 24.26 km/sec
Occultation Star USNOB R magnitude 16.182

1One standard deviation of random error.
2The UCAC bandpass (579-642nm) is between V and R.


Table 2: Reference Star Position
Reference star position:
(UCAC2, at epoch of event)
RA (h:m:s; J2000) Dec (d:m:s; J2000) Notes
84522.20131010 Catalog 02 14 15.9967 ± 0.0970 +24 51 18.427 ± 0.150
84522.20131010 Measured3 02 14 16.0028 ± 0.0034 +24 51 17.992 ± 0.013
From 5 Lowell 42-inch frames
Table 3: Projected KBO Offsets from Reference Ephemeris at the Time of the Event
Body RA (arcsec) Dec (arcsec)  
84522

0.2107 ± 0.0904

–0.242 ± 0.111 See Notes 5 and 6

3Measured position corresponds to RA offset of +0.0829 and Dec. offset of –0.436.

4All "offsets" are defined in the ("corrected" – "reference") or ("observed" – "calculated") sense. The offsets should be added to reference positions to get the measured positions, which we use to calculate the prediction.

4Data analyzed using UCAC2 reference network. A weighted average of the data from the two telescopes was used to calculate the RA and DEC. The errors given are 1 standard deviation.

5The reference positions for Haumea are those given by JPL Horizon's ephemeris (84522 source file: JPL9; Earth center source file: DE405).

6Data from the USNO 61-inch, SMARTS 0.9m, and Lowell 42-inch telescopes over the span of 3 years were reduced with respect to stars in the UCAC2 catalog. A model was developed to fit the residuals obtained from our measured positions compared to that of the object's JPL ephemeris. All residuals obtained from the different telescopes were consistent with the model. The model includes the first-order effects of errors in the orbital elements of 84522: (i) constant offsets in RA and Dec, (ii) linear (in time) offsets in RA and Dec, and (iii) sinusoidal terms with the Earth's orbital period. The model was propagated to obtain the predicted position and error of the KBO at the time of the occultation. The errors listed for the KBO are 1 standard deviation.

 

Table 4: Site Information

Site
East Longitude
Latitude

Site Altitude6

(km)

Distance7

(km)

Velocity

(km/s)

CTIO
–70 48 54
–30 09 54
2.215
5268 S.
24.66
Haleakala
–156 15 24
+20 42 24
3.054
2009 N.
24.35
Hartung Boothroyd Observatory
–76 23 04
42 27 29
0.534
1815 N.
24.60
Magdalena Ridge Obs
–107 11 05
+33 58 36
2.219
1433 N.
24.60
McDonald Obs
–104 01 21
+30 40 17
2.076
1005 N.
24.62
SVH
–74 56 45
40 57 41
0.220
1646 N.
24.61
Wallace
–71 29 06
42 36 36
0.107
1806 N.
24.60
Williams
–73 12 06
42 42 42
0.215
1824 N.
24.60
Geocenter
----------
---------
center of Earth
24 N.
24.26

6Altitude of each observatory is measured in kilometers above sea level.

7"Distance" refers to the closest approach distance of the "Site" to the center of 84522's shadow in the shadow plane. The errors on all closest approach distances are ±1023 km (one standard deviation). "S." means the site is south of the center of 84522's shadow. "N." means the site is north of the center of 84522's shadow.

Table 5: 84522.20131010 Occultation Predictions for Individual Sites

Site
KBO Immersion (UT)9
UT Mid-Time
KBO Altitude
Solar Altitude9

KBO Emersion (UT)9

CTIO
-----------
06:41:27
33
-----------
-----------
Haleakala
-----------
06:45:35
27
-----------
-----------
Hartung Boothroyd Observatory
-----------
06:41:10
70
-----------
-----------
Magdalena Ridge Obs
-----------
06:43:04
70
-----------
-----------
McDonald Obs
-----------
06:42:58
74
-----------
-----------
SVH
-----------
06:41:06
72
-----------
-----------
Wallace
-----------
06:40:54
68
-----------
-----------
Williams
-----------
06:41:00
69
-----------
-----------
Geocenter
06:41:28
06:41:53
-----------
-----------
06:42:18

9The errors on all times are ±1:59 (1 minutes, 59 seconds; one standard deviation). The solar altitude is given for locations where it is relevant (solar altitude greater than -18°). No entry in the immersion and emersion columns indicates that the occultation is not predicted to be visible at that site.


Last updated by Carlos Zuluaga (czuluaga@mit.edu) 2013-09-18 15:10

Please direct all inquiries to PAL (planetary-astronomy@mit.edu)